Smoking has a negative effect on several types of eye disease. But so far, medical studies have not proven a direct link between smoking and glaucoma.

Despite the lack of proof, most doctors recommend that people with glaucoma quit cigarettes. Here's why:

Pressure within the eye increases in people with glaucoma. Higher pressure is related to an increased risk of glaucoma-related vision loss.

Eye pressure is determined by measuring the amount of fluid in a chamber in the front part of the eye. This fluid is called aqueous humor. The eye continually produces new aqueous humor. Normally, eye pressure stays constant because the eye reabsorbs the same amount of fluid that it produces.

People with glaucoma produce too much fluid or don’t reabsorb enough. This makes their eye pressure rise.

Smoking causes blood vessels to tighten or constrict. When this happens, blood vessels in the eye have less capacity to reabsorb the aqueous humor. Logic suggests that eye pressure would therefore increase.

There is a definite association between smoking and an increased risk of developing cataracts and macular degeneration. So, even if smoking doesn’t affect glaucoma, it’s wise for people with glaucoma to avoid tobacco to reduce any risk of adding a second eye disease.